Automating Signals

In preparation of buying some signals for the layout, I considered the prospect of placing a couple of Home signals on the layout. I wanted to control these signals with a button and make the signal drop to red after the train goes past it.

I saw this as two issues:

1. The ability to control the signal just like in CTC and to have the circuit detect the passing of a train to drop the signal to red.

2. The detection circuit.

Now, railpage user JLB51 has helped me tremendously. He provided me with a circuit that uses two 555 ICs. The first 555 is used to drive the RED led whilst the second is used to drive the GREEN. The first 555 is set up as a bistable circuit whilst the second as an Inverting Buffer or Schmitt trigger. Thanks to JLB51, I was able to create his circuit on a breadboard and to my delight the circuit worked! Here are some pictures

This one shows the signal set to Green.




This one shows the signal set to RED




Now, I need the detection circuit! Again, JLB51 has kindly provided me with some valuable information to get started on this.